You can have too much of a good thing, at least when it comes to exercise. Excessive amounts of exercise can lead to fertility problems including irregular periods, anovulatory cycles (cycles in which ovulation does not occur), and luteal phase deficiencies (a problem that occurs when the second half of your cycle isn’t long enough to allow for the proper implantation of the fertilized egg).
When the amount of exercise exceeds the body's ability to recover, instead of getting faster and stronger, you can actually end up becoming slower and weaker (not to mention sick and injured). Give yourself at least one or two days off every week to allow your body to recover. The moral of the story? Stay active, but don’t overdo it.